The present invention relates to a control system for conveyors, and more particularly to a pneumatic system for controlling a zero pressure accumulating conveyor.
The term "zero pressure", as used in the context of accumulating conveyors, refers to an accumulating conveyor having controlled spacing between the containers, pallets or other articles being conveyed. Controlled spacing prevents contact between the conveyed articles which in turn minimizes any damage resulting from the conveying process. Controlled spacing is generally achieved by using a conveyor system having a plurality of independently controlled segments or zones.
Zero pressure accumulating conveyors employing pneumatic control systems are known in the art. An example of one such arrangement is disclosed in U.S. Pat. application Ser. No. 944,131, now U.S. Pat. No. 4,264,004, filed Sept. 20, 1978, by Warren J. Harwick, entitled "Control System For Accumulating Conveyors", and assigned to the assignee of the present application. U.S. Pat. No. 4,264,004 discloses the use of AND valves in a pneumatic logic system for controlling a zero pressure accumulating conveyor.
While accumulating conveyors having zero pressure and employing pneumatic control systems are known in the art, there remains a need for versatile control systems which can be economically manufactured and installed and which offer flexibility in operation and design.